Digital scope targets industrial power users

The instrumentation maker, Tektronix, has developed a portable four-channel digital storage oscilloscope (DSO) specifically for use in industrial power applications. The scope can be used to measure and characterise switching losses, waveforms, pulse durations, harmonic content and other parameters in three-phase variable speed drive installations.

Conventional oscilloscopes often cannot be used in such applications because of the high voltages and currents, and because of the presence of floating electrical signals which are not referenced to earth. Any attempt to attach a standard oscilloscope whose chassis is hard-wired to earth, without using differential probes, can create dangerous short-circuits in such installations.

The new DSOs use a patent-pending technology which separates and disconnects all signal inputs, including the external trigger input, from the AC supply earth. There is also full isolation from channel-to-channel and from the inputs to the chassis. Up to four test points can be connected simultaneously, without earthing conflicts.

The TPS2000 oscilloscope comes with probes that can measure up to 30VRMS floating on up to four channels simultaneously. Optional high-voltage probes allow measurements up to 600VRMS Cat II (or 330VRMS Cat III) floating.

Tektronix has also produced a new power measurement and analysis software package for automated power, waveform and phase analysis. It can also calculate items such as switching losses, harmonics (to the 50th), true, reactive and peak power, crest factors, phase relationships and power factors.

The oscilloscopes, which weigh about the same as a laptop computer, provide up to eight hours of operation from one set of hot-swappable batteries.